1. Field of the Invention
This invention relates to a saddle type small-sized boat wherein a four-cycle engine having a head cover is carried in a boat body. More particularly, the present invention relates to the head cover and a cylinder head of the four-cycle engine of the saddle type small-sized boat.
2. Description of Background Art
Conventionally, a small-sized boat as shown in FIGS. 9(a) and 9(b) is known as a saddle type small-sized boat wherein a four-cycle engine having a head cover is carried in a boat body (Japanese Patent Laid-Open NO. Hei. 10 252440).
FIGS. 9(a) and 9(b) are front elevational sectional views of the boat. FIG. 9(a) shows the boat in an ordinary state and 9(b) shows the boat in a capsized state. The surface of the water is designated by the letter H.
As shown in FIG. 9(a), the boat 1 includes a four-cycle engine 3 carried in a boat body 2 and further includes a jet pump not shown which is driven by the four-cycle engine 3.
A breather exit 4a is provided in a head cover 4 of the engine 3 and is connected to an intake apparatus 6 by a breather pipe 5.
Accordingly, with the engine 3 having such a construction as just described, blowby gas leaking out into the head cover 4 is allowed to flow back and be burnt.
Further, a hole (not shown) through which a plug (ignition plug) is to be mounted and dismounted is formed in the head cover 4, and a bearing surface (not shown) for a plug is formed on a cylinder head.
Since a saddle type small-sized boat of the type described is used principally for leisure, it is capsized frequently, and water sometimes enters the boat body.
In such a situation as just described, the conventional saddle type small-sized boat as illustrated in FIGS. 9(a) and 9(b) and as described above has the following problems.
If the boat 1 is capsized as shown in (b) of FIG. 9, then oil in the engine 3 flows downwardly (toward the head cover 4). However, the oil cannot be stored sufficiently by the conventional head cover 4, and there is the possibility that the oil may flow from the breather exit 4a through the breather pipe 5 into the intake apparatus 6, resulting in contamination of the intake apparatus 6 with the oil. Further, if the oil flows out from the intake apparatus 6, then there is the possibility that the inside of the boat body 2 may also be contaminated with the oil.
With the conventional saddle type small-sized boat as illustrated in FIGS. 9(a) and 9(b), if water entering the boat body splashes on the head cover 4, then the water stays in the plug mounting-dismounting hole and sometimes causes trouble with an electric apparatus.
Particularly when the saddle type small-sized boat is turned back as shown in FIG. 9(a) by a user after it is capsized as shown in FIG. 9(b), water splashes by a large amount on the head cover 4, and the water is liable to stay in the plug mounting-dismounting hole and cause trouble with the electric apparatus.
It is a first object of the present invention to solve the problems described above and provide a saddle type small-sized boat wherein an intake apparatus and the inside of a boat body is less likely to be contaminated with oil.
It is a second object of the present invention to solve the problems described above and provide a saddle type small-sized boat which is less likely to suffer from causing trouble to an electric apparatus.
To attain the first object of the present invention, a saddle type small-sized boat is provided wherein a four-cycle engine having a head cover in which a breather exit is formed is carried in a boat body and the head over forms an oil storage portion when the boat is capsized. The oil storage portion is configured such that an upper face of the head cover is positioned close to a ceiling of the boat body and extends along the ceiling. In addition, the breather exit is provided above an upper face of any oil that is stored in the head cover when the boat is capsized.
A saddle type small-sized boat of the present invention is directed to a four-cycle engine having a head cover in which a breather exit is connected to an intake apparatus by a breather pipe, and a connection portion of the breather pipe to the intake apparatus is positioned below the breather exit.
A saddle type small-sized boat according to the present invention provides a breather exit on an upstream side with respect to a turning direction when the boat is turned back after capsized.
A saddle type small-sized boat according to the present invention provides a four-cycle engine having a head cover in which a plug mounting-dismounting hole is formed and the head cover has a water drain path formed therein which connects to the plug mounting-dismounting hole and is opened to a peripheral face of the head cover rearwardly of the hole with respect to an advancing direction of the boat body.
A saddle type small-sized boat according to the present invention is provided wherein the four-cycle engine is a DOHC engine having intake and exhaust camshafts independent of each other, and the water drain path of the head cover extends in the rear of a cam cover portion of the head cover which covers cam portions of the camshafts with respect to the advancing direction of the boat body and is opened to a peripheral face of the head cover.
A saddle type small-sized boat according to the present invention is provided wherein an upper face of a cylinder head of the engine is inclined as viewed from the front of the boat body, and the water drain path is opened downwardly in a direction of the inclination.
A saddle type small-sized boat according to the present invention is provided wherein the water drain path is opened to a downstream side of the plug mounting-dismounting hole with respect to a turning direction when the boat body is turned back after capsized.
A saddle type small-sized boat according to the present invention is provided with an engine having a plug mounting-dismounting hole and a plug bearing surface which are inclined as viewed from the front of a boat body and includes a water drain flow path that is formed at lowermost end portions of the plug mounting-dismounting hole and the plug bearing surface.
A saddle type small-sized boat according to the present invention is provided with water drain flow path on the downstream side of the plug mounting-dismounting hole and the plug bearing surface with respect to a turning direction when the boat is turned back after the boat has capsized.
It is to be noted that the turning direction when the boat is turned back after the boat has capsized is indicated in a user""s manual, on the boat body and so forth.
A saddle type small-sized boat provides a head cover for a four-cycle engine with a breather exit formed in the boat body. An oil storage portion is provided when the boat is capsized wherein oil flowing downwardly (toward the head cover) when the boat is capsized is stored by the head cover.
Since the upper face of the head cover is positioned close to the ceiling of the boat body and extends along the ceiling, the containing capacity of the head cover can be increased, and the stored amount of the oil by the head cover is assured sufficiently.
Further, since the breather exit described above is provided above the upper face of the oil stored in the head cover when the boat is capsized, such a situation wherein the oil flows out through the breather exit is less likely to occur.
Accordingly, with the saddle type small-sized boat a situation where the oil flows out from the head cover when the saddle type small-sized boat is capsized is less likely to occur. As a result, an advantage occurs in that an intake apparatus and the inside of the boat body are less likely to be contaminated with the oil. In addition, since the containing capacity of the head cover can be increased, the breathing performance is augmented.
In other words, with the saddle type small-sized boat according to the present invention a situation occurs where the oil flowing out is less likely to occur and simultaneously the breathing performance is augmented.
With the saddle type small-sized boat according to the present invention, since a breather exit of the saddle type small-sized boat with the four-cycle engine having the head cover is provided in which the breather exit is formed in the boat body and is connected to the intake apparatus by the breather pipe, blowby gas leaking out into the head cover is allowed to be flow back and be burnt.
Further, since the connection portion of the intake apparatus to the breather pipe is positioned below the breather exit described above, when the boat is capsized, the connection portion of the intake apparatus to the breather pipe is positioned above the breather exit described above.
Accordingly, when the boat is capsized, the oil is less likely to flow from the breather exit of the head cover to the intake apparatus, and as a result, an effect that the intake apparatus and the inside of the boat body are less likely to be contaminated with the oil is attained.
With the saddle type small-sized boat according to the present invention, since the breather exit in the saddle type small boat is provided on the upstream side with respect to the turning direction when the boat is turned back after the boat has capsized, a situation wherein the oil flows out through the breather exit when the boat is turned back after capsized does not occur.
Accordingly, when the boat is turned back after the boat has capsized, the intake apparatus and the inside of the boat body are prevented from being contaminated with the oil.
With the saddle type small-sized boat according to the present invention, since the head cover of the saddle type small-sized boat with the four-cycle engine having the head cover in which the plug mounting-dismounting hole is formed is carried in the boat body and is formed therein with the water drain path which is connected to the plug mounting-dismounting hole and is opened to the peripheral face of the head cover rearwardly of the hole with respect to the advancing direction of the boat body, water is less liable to stay in the plug mounting-dismounting hole in the head cover as described below.
In particular, a saddle type small-sized boat of this type is inclined during operation thereof such that the forward portion thereof in the advancing direction is directed upwardly and the rear portion is directed downwardly.
Further, with the saddle type small-sized boat according to the present invention, since the water drain path is connected to the plug mounting-dismounting hole and is opened to the peripheral face of the head cover rearwardly of the hole with respect to the advancing direction of the boat body, water is less liable to stay in the plug mounting-dismounting hole. Accordingly, an electric apparatus is less likely to suffer from any trouble.
With the saddle type small-sized boat according to the present invention, since the four-cycle engine in the saddle type small-sized boat is a DOHC engine having intake and exhaust camshafts independent of each other and the water drain path of the head cover extends to the rear of the cam cover portion of the head cover which covers the cam portions of the camshafts and is opened to the peripheral face of the head cover, the water drain path of the DOHC engine which has the intake and exhaust camshafts independent of each other can be formed efficiently.
With the saddle type small-sized boat according to the present invention, since the upper face of the cylinder head of the engine in the saddle type small-sized boat is inclined as viewed from the front of the boat body and the water drain path is opened downwardly in the inclination direction of the upper face, water is much less likely to stay in the plug mounting-dismounting hole, and accordingly, the electric apparatus is much less likely to suffer from any trouble.
With the saddle type small-sized boat according to the present invention, since the water drain path in the saddle type small-sized boat is opened toward the downstream side of the plug mounting-dismounting hole with respect to the turning direction when the boat is turned back after the boat has capsized, water is much less likely to stay in the plug mounting-dismounting hole as described below, and accordingly, an electric apparatus is much less likely to suffer from any trouble.
In particular, when the boat is turned back by the user after the boat has capsized, a large amount of water sometimes splashes on the head cover. With the saddle type small-sized boat according to the present invention, however, since the water drain path is opened toward the downstream side of the plug mounting-dismounting hole with respect to the turning direction when the boat is turned back after the boat has capsized, even if a large amount of water splashes on the head cover in the process wherein the boat is turned back, the water is discharged with certainty from the plug mounting-dismounting hole past the water drain path.
Accordingly, when the boat is turned back after the boat has capsized, water is less likely to stay in the plug mounting-dismounting hole, and accordingly, an electric apparatus is less likely to suffer from any trouble.
With the saddle type small-sized boat according to the present invention, since the water drain flow path is formed at the lowermost end portions of the plug mounting-dismounting hole and the plug bearing surface of the saddle type small-sized boat and the engine having the plug mounting-dismounting hole and the plug bearing surface which are inclined as viewed from the front of the boat body is carried in the boat body, water does not stay around the plug mounting-dismounting hole and the plug bearing surface, and an electric apparatus is less likely to suffer from any trouble.
With the saddle type small-sized boat according to the present invention, since the water drain flow path in the saddle type small-sized boat is provided on the downstream side of the plug mounting-dismounting hole and the plug bearing surface with respect to the turning direction when the boat is turned back after the boat has capsized, even if a large amount of water splashes around the plug mounting-dismounting hole and the plug bearing surface in the process wherein the boat is turned back, the water is discharged with certainty past the water drain flow path. Accordingly, water is less liable to stay around the plug mounting-dismounting hole and the plug bearing surface after the boat is turned back after capsized, and accordingly, the electric apparatus is less likely to suffer from a trouble.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.